Results 161 to 170 of about 4,294 (185)
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Autofocusing in digital holography
SPIE Proceedings, 2013Digital holography allows the acquisition of 3D profiles of objects. Digitally captured holograms are reconstructed at the respective distances of the objects to reveal the phase and the intensity profiles. However, computing an object’s 3D profile with only a single reconstruction requires prior knowledge of the distance of the object from the ...
Meriç Özcan +2 more
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Multifocus autofocusing Airy beam
Journal of the Optical Society of America A, 2017We propose a multifocus autofocusing Airy beam (MAAB) by modifying the frequency spectrum of a symmetric Airy beam (SAB) with a Gaussian band elimination filter. Unlike the original SAB, there are four off-axis foci at the autofocusing plane of the MAAB. The MAAB has a better abruptly autofocusing property than the original SAB.
Fei Zi +3 more
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An autofocusing algorithm for digital holograms
SPIE Proceedings, 2012We propose an algorithm for the automatic estimation of the in-focus image and the recovery of the correct reconstruction distance for digital holograms. We tested the proposed approach applying it to stretched digital holograms. In fact, by stretching an hologram with a variable elongation parameter, it is possible to change the in-focus distance of ...
Ferraro P +5 more
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A survey on ISAR autofocusing techniques
2004 International Conference on Image Processing, 2004. ICIP '04., 2005Over many years of research, several ISAR autofocusing techniques have been proposed. Today, we can divide them into two main categories: parametric and non-parametric techniques. The prominent point processing and the phase gradient algorithm are two classical examples of non-parametric techniques, whereas the more recent image contrast and entropy ...
BERIZZI, FABRIZIO +4 more
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Three-Airy autofocusing beams*
Chinese Physics B, 2020We numerically and experimentally demonstrate that a three-Airy autofocusing beam can be generated by superposing three deformed two-dimensional (2D) Airy beams with a triangle symmetry. When the initial angle between two wings of the deformed 2D Airy beams increases, such a three-Airy autofocusing beam exhibits that the focusing length decreases and ...
Cibo Lou +4 more
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Observation of abruptly autofocusing waves
Optics Letters, 2011We report on the experimental observation of abruptly autofocusing waves. This interesting family of wave packets has been realized by using a radially symmetric Airy intensity distribution. As demonstrated in our experiments, these waves can exhibit unusual features, such as the ability to autofocus by following a parabolic trajectory toward their ...
Papazoglou, Dimitrios G. +3 more
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Separation of antibiotics by autofocusing
ELECTROPHORESIS, 1990AbstractThe autofocusing separation of nine antibiotics was investigated: tetracycline and chloramphenicol in large‐scale batches, and seven others in gram preparation amounts. All except one were found to be hetergeneous in autofocusing, and 2‐4 well‐characterized fractions emerged. These heterogeneities are described and the industrial utilization of
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The autofocusing system of the IMAT neutron camera
Review of Scientific Instruments, 2013In this paper, we present the autofocusing system of the imaging instrument to be used on IMAT, a new neutron-imaging facility under construction at the ISIS (UK) target station 2. We have compared 16 different autofocus algorithms to select the one with the best performance. The algorithms have been evaluated by using both a qualitative analysis and a
V Finocchiaro +5 more
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Autofocusing for tissue microscopy
Image and Vision Computing, 1993Abstract This paper describes the implementation of autofocusing for tissue microscopy. We first investigate the suitability of several criterion functions for the evaluation of image sharpness. Since tissue sections are invariably stained, we also discuss the selection of the colour component on which autofocusing will be performed.
Yeo, T. +3 more
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Edge-Preserving Autofocusing in Digital Holography
Digital Holography and Three-Dimensional Imaging, 2016In digital holography, it is essential to know the axial position of the recorded object for reconstruction. Here we propose an autofocusing algorithm using structure tensor to determine the focal distance and to extract the edge information.
Ren, Z, Lam, EYM
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